Quick-connect chuck mechanism

ABSTRACT

A chuck is provided for retaining the shank of a tool bit or accessory, having a fixed diameter, inserted in a central channel at a distal end of the chuck. At least one torsion spring is mounted axially within a housing and has an inner dimension and shape comparable to the shank&#39;s outer dimension and shape. A mechanism winds and unwinds the torsion spring to respectively grip or release said shank, the winding being in a rotational direction consistent with a normal operating rotational direction of said chuck such that said shank tends to further wind the torsion spring for further self-tightening in normal operation.

FIELD OF THE INVENTION

This is a formal application based on and claiming the benefit ofprovisional application No. 60/400,037, filed Aug. 2, 2002.

The present invention relates generally to power tools and accessories.More particularly, the present invention relates to an improved chuckfor use with a rotary and/or hobby tool.

BACKGROUND OF THE INVENTION

This invention relates to accessories for rotary tools. Morespecifically, this invention relates to mechanisms or chucks forretaining, preferably round shanked tool bits or accessories forpreferably unidirectional rotary tools such as those sold under theDremel, Black & Decker or Craftsman trademarks that offer conventionalmethods to achieve tool change and holding capability.

Due to problems associated with gripping and driving tool bits withround shanks, one known solution is via a collet and a tightening nut,which is rotated to secure the shank of the tool bit. The shortcoming ofthis design is the cumbersome and time-consuming tool changes.Generally, a spindle of the rotary tool is locked in one position andheld there. A separate tool; such as an open-ended wrench, is used toengage the nut to loosen it from the collet. The tool bit or accessoryis then removed from the tool. To install another accessory, the reverseoperation is performed. The spindle is locked into place again and heldin that position. The shank of the tool bit or accessory is insertedinto the collet and the nut is tightened. An open-ended wrench is usedto securely tighten the shank in the collet. As well as being tootime-consuming, this method is also inconvenient since a user grasps thetool and locks the spindle in place, while simultaneously inserting theaccessory into the collet and tightening the nut around the shank of theaccessory. This method also requires the use of a separate tool totighten and loosen the shank of the accessory from the collet.

Another method of attaching accessories to rotary tools is by using athree-jaw chuck. In this method, again, the spindle of the tool islocked into position, while the chuck is tightened on the shank of thetool bit or accessory. In some cases, a separate tool, such as a wrenchor Allen key, is used to tighten or loosen the chuck once it has beenfinger-tightened. This method again requires the user to change the toolbit or accessory using both hands when there are three areas the usermust contact: the spindle, the shank, and the chuck.

There is a need for a mechanism that provides quicker tool changing yetequals or betters the mechanism's capability to hold the tool in itsoperation. There is also a need for a mechanism that does not requireany extra tools for operation.

It is, therefore, desirable to provide an improved chuck for a use witha rotary tool.

SUMMARY OF THE INVENTION

It is an object of the present invention to obviate or mitigate at leastone disadvantage of previous chucks for rotary tools by providing achuck that accommodates and provide torque to tools with preferablyround shanks.

In a first aspect, the present invention provides a chuck for retainingthe shank of a tool bit or accessory inserted in a central channel at adistal end of said chuck, comprising at least one torsion spring mountedaxially within a housing and having an inner dimension and shapecomparable to said shank's outer dimension and shape, and mechanicalmeans for winding and unwinding said torsion spring to respectively gripor release said shank, said winding being in a rotational directionconsistent with a normal operating rotational direction of said chucksuch that said shank tends to further wind said torsion spring forfurther self-tightening in normal operation.

In another aspect, the present invention provides a chuck for retainingthe shank of a tool bit or accessory inserted into a central channel ata distal end of said chuck comprising a collet with at least two jawsmounted axially within a moveable sleeve, axial movement of said sleevein one direction causing expansion of said at least two jaws to permittool bit removal and axial movement in a second direction causinggripping of said tool bit by said device.

In yet a further embodiment, the present invention provides a chuck forretaining the shank of a tool bit or accessory inserted into a centralchannel at a distal end of said chuck comprising a collet with at leasttwo jaws, mounted axially within a moveable sleeve, fractionalrotational movement of said sleeve in one direction causing expansion ofsaid at least two jaws to permit tool bit removal and fractionalrotational movement in a second direction causing gripping of said toolbit by said device.

Other aspects and features of the present invention will become apparentto those ordinarily skilled in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the attached Figures, wherein:

FIG. 1 is an exploded view of a first embodiment of a chuck for use witha rotary tool;

FIG. 2 a is a side view of a torsion spring used in the first embodimentof the chuck;

FIG. 2 b is an isometric view of the torsion spring used in the firstembodiment of the chuck;

FIG. 3 a is an isometric view of an inner housing for the firstembodiment of the chuck;

FIG. 3 b is an isometric view of the inner housing;

FIG. 4 a is an isometric view of a sleeve used in the first embodimentof the chuck;

FIG. 4 b is a transparent isometric view of the sleeve;

FIG. 4 c is a sectional view of the sleeve;

FIG. 5 a is an isometric view of the end cap of the first embodiment ofthe chuck;

FIG. 5 b is a side view of the end cap;

FIG. 6 a is a cross-sectional view of the first embodiment of theassembled chuck in the locked position with a tool bit or accessory;

FIG. 6 b is a cross-sectional view of the end of the assembled chuck inthe locked position with a tool bit or accessory;

FIG. 7 a is a cross-sectional view of the assembled chuck in the openposition;

FIG. 7 b is a cross-sectional view of the end of the assembled chuck inthe open position;

FIG. 8 is a cross-sectional view of the second embodiment of the chuckfor a rotary tool in the locked position;

FIG. 9 is a cross-sectional view of the end of the second embodiment ofthe chuck for a rotary tool in the locked position as indicated in FIG.8;

FIG. 10 is a cross-sectional view of the second embodiment of the chuckfor a rotary tool in the open position;

FIG. 11 is a detail drawing of the torsion spring as indicated in FIG.10;

FIG. 12 is a cross-sectional view of the end of the second embodiment ofthe chuck for a rotary tool in the locked position as indicated in FIG.10;

FIG. 13 is a cross-sectional view of the second embodiment of the chuckfor a rotary tool in the open position with the tool bit or accessoryremoved;

FIG. 14 is a cross-sectional view of the inner housing of the secondembodiment of the chuck;

FIG. 15 is a side view of the inner housing of the second embodiment ofthe chuck;

FIG. 16 is an end view of the inner housing as shown in FIG. 15;

FIG. 17 is a side view opposite that of FIG. 15 of the inner housing ofthe second embodiment of the chuck;

FIG. 18 is an end view of the inner housing as shown in FIG. 17;

FIG. 19 is an isometric view of the inner housing of the secondembodiment of the chuck;

FIG. 20 is a side view of the sleeve of the second embodiment of thechuck;

FIG. 21 is a cross-sectional view of the sleeve as shown in FIG. 20;

FIG. 22 is an isometric view of the sleeve of the second embodiment ofthe chuck;

FIG. 23 is a sectional view of the sleeve as shown in FIG. 22;

FIG. 24 is an end view of the torsion spring of the second embodiment ofthe chuck;

FIG. 25 is a side view of the torsion spring as shown in FIG. 24;

FIG. 26 is an isometric view of the inner housing and the torsion springof the second embodiment;

FIG. 27 is a sectional view of the inner housing with the sleeve in thelocked position;

FIG. 28 is a sectional view of the inner housing with the sleeve in theopen position;

FIG. 29 is a detailed view of the torsion spring within theinnerhousing;

FIG. 30 is a cross-sectional view of a third embodiment of the chuck inthe open position;

FIG. 31 is a cross-sectional view of a third embodiment of the chuckwith a tool bit or accessory in the locked position;

FIG. 32 is a cross-sectional view of the third embodiment of the chuckin the locked position;

FIG. 33 is an exploded view of the third embodiment of the chuck;

FIG. 34 is a cross-sectional view of a fourth embodiment of the chuck inthe open position;

FIG. 35 is a cross-sectional view of the fourth embodiment of the chuckin the locked position;

FIG. 36 is a side view of the spring used in the third and fourthembodiment of the chuck;

FIG. 37 is an isometric view of the spring as shown in FIG. 36;

FIG. 38 is a bottom view of the spring in FIG. 36;

FIG. 39 is a cross section of the inner housing of the fourth embodimentof the chuck;

FIG. 40 is an end view of the inner housing as shown in FIG. 39;

FIG. 41 is a side view of the sleeve of the third and fourth embodimentof the chuck;

FIG. 42 is an end view of the sleeve shown in FIG. 41;

FIG. 43 is an end view of the tool bit or accessory used in the fourthembodiment of the chuck;

FIG. 44 is a side view of the tool bit or accessory shown in FIG. 43.

FIG. 45 is a side view of the inclined plate used in the third andfourth embodiment of the chuck;

FIG. 46 is an end view of the inclined plate shown in FIG. 45;

FIG. 47 is a cross-sectional view of the end cap used in the third andfourth embodiment of the chuck;

FIG. 48 is an end view of the end cap shown in FIG. 48;

FIG. 49 is a cross-sectional view of a fifth embodiment of the chuck inthe locked position with a tool bit or accessory.

FIG. 50 is a sectional of a sixth embodiment of the chuck.

DETAILED DESCRIPTION

Generally, the present invention provides an improved chuck for a rotarytool.

Turning to FIG. 1, an exploded view of apparatus of a chuck for a rotarytool is shown. The chuck 10 comprises an inner housing 12, acompression, or biasing, spring 14, a second spring 16, such as atorsion spring, a mid spacer 18, an end spacer 20, an inclined plate 22,a sleeve 24, an end cap 26 and a spring cap 28. As will be explained ingreater detail later, the mid spacer 18, the end spacer and the inclinedplate 22 are strictly optional features.

As shown in FIGS. 2 a and 2 b, the torsion spring 16 comprises a pair ofspring sections 30 a and 30 b, each having an end tang 32 a and 32 b,which are connected to each other via a moveable tang portion, such as acentral tang 34. In another embodiment, a pair of springs comprising acentral tang and a pair of end tangs may also be used.

FIGS. 3 a and 3 b provide more detailed schematics of the inner housing12. FIG. 3 a is a perspective view of the top of the inner housing andFIG. 3 b is a perspective view of the bottom of the inner housing 12.The inner housing 12 comprises a first end 36 for receiving a shank of atool bit or accessory and a second end 38 for attachment of the chuck 10to a power tool. Examples of a tool bit or accessory include a drillbit, a mandrel or a grinding tool.

The first end 36 is preferably a cylindrical tube comprising a tang slot40, preferably manufactured by milling, for receiving the end tangs 32 aand 32 b and the central tang 34 of the torsion spring 16 along with acentral channel 42 for receiving the two spring sections 30 a and 30 b.The tang slot 40 comprises a radial, or circumferential, slot 44 forhousing the central tang 34 after the torsion spring 16 has beeninserted into the channel 42. The hole 44 provides an area for thecentral tang 34 to rotate when the sleeve is moved (as will be describedbelow) along with an area for the central tang 34 to rotate in order totighten the torsion spring 16 around the shank of the tool bit oraccessory. After the torsion spring 16 has been inserted into the firstend 36 of the inner housing 12, the spring cap 28, preferably a polymercylinder, is fitted atop the central tang 34. The spring cap 28 providesprotection to the central tang 34 from wear and tear against the sleeveand to reduce friction between the central tang 34 and the sleeve 24.Alternatives to the polymer cylinder include an oilite-type cylinder orany other bushing that is lubricant-impregnated.

The mid spacer 18 is placed between the two springs sections 30 a and 30b to provide stability to the shank of the tool bit or accessory whenthe tool bit or accessory is inserted into the chuck. The mid spacer 18also provides support for short shanks or shanks that have not beeninserted to a required depth. The mid spacer 18 preferably has an outerdiameter smaller than the diameter of the central channel 42 and aninternal diameter slightly larger than that of the shank of the tool bitor accessory. Although the term diameter has been used to describe theapertures within which the shank of the tool bit or accessory isreceived, other dimensions may be used depending on the shape of theouter dimension of the shank.

A ridge, corresponding to the dimension of the end of the shank, whichis cylindrical in the preferred embodiment but may be any shape such asnotched or non-cylindrical, within the central channel 42 acts as astopper to prevent the torsion spring 16 from entering the second end 38of the inner housing 12. The inner diameter of the ridge is also sizedto provide stability to the shank of the tool bit or accessory. An endportion, seen as a pair of prongs 46, is located opposite the annularridge for connection with the end cap 26 when the chuck 10 is assembled.

The first end 36 of the inner housing 12 further comprises a second slot48, seen as an alignment slot, for receiving an aligner such as a key.The key is preferably formed integral to the inside of the sleeve 24 aswill be discussed in more detail below. The location of the alignmentslot 48 is generally opposite to and substantially equal in length withthe tang slot 40.

The second end 38 of the inner housing 12 comprises a shoulder 50 havinga diameter larger than the outer diameter of the first end 36. Theshoulder 50 comprises a centrifugally movable means, seen as a set ofholes 52, each containing a spherical ball, preferably six, arranged atpredetermined intervals around the surface of the shoulder 50. Thecentrifugally movable means prevent axial displacement or removal of thesleeve during use. A pair of flats 54 is also milled on the side of theshoulder 50 away from the first end 36 to assist in the tightening ofthe second end 38 onto the spindle of the power tool.

The compression spring 14 is assembled over the cylindrical tube of thefirst end 36 and has one end abutting the shoulder 50 and its other endabutting a shoulder 64 within the sleeve 24. It will be understood thatthe compression spring 14 is assembled over the cylindrical tube beforethe torsion spring 16 is inserted into the central channel 42.

Turning to FIGS. 4 a to 4 c, more detailed schematics of the sleeve 24are shown. FIG. 4 a is a perspective view from an end of the sleeve 24.FIG. 4 b is a perspective view of the sleeve with broken linesindicating details within the sleeve 24 and FIG. 4 c is a sectional viewof the sleeve 24. The sleeve 24, which is preferably cylindricallyshaped, comprises a first end 54 having an inner diameter which is lessthan the inner diameter of a second end 56.

The first end 54 of the sleeve 24 receives the end cap 26 while thesecond end 56 is shaped to form an inclined face 58 adjacent astraight-walled cross-section 60. An annular recess 62 is formed in thesleeve 24 to create the shoulder 64 along with a cam 66, which in thepresent embodiment is helical. The shoulder and the internal cam withinthe sleeve assist in providing mechanical means for winding andunwinding the torsion spring 16.

The sleeve 24 may be manufactured in a variety of methods includingpressing, powder metal, injection moulding, die-casting, machining or acombination thereof but in the preferred embodiment is a die-cast piece.The preferred embodiment further comprises an aligner 44 45, formed onthe internal diameter of the sleeve 24, sized to fit within thealignment slot 48 in the first end 36 of the inner housing 12. Thealigner 44 45 provides support when the chuck 10 is in use to preventthe sleeve 24 from unwanted rotational motion. The aligner also servesas a means to guide the sleeve when it is assembled over the innerhousing.

When assembled to the inner housing 12, the sleeve 24 is oriented sothat the aligner 44 45 is inserted into the alignment slot 48 with theinternal cam 66 contacting the spring cap 28 covering the central tang34. The sleeve 24 fits over the entire inner housing 12 to retain thespherical balls in the set of holes 52, the compression spring 14, andthe aligner 44 45.

Turning back to FIG. 1, the optional inclined plate 22 is positionedadjacent to, and held in place by, the end spacer 20 to reduceaccidental axial movement of the shank of the tool bit or accessorywhile the chuck 10 is in use. The inclined plate 22 is generallycircular and has an internal diameter similar to the inner diameter ofthe mid-spacer 18 and the end-spacer 20. A tab 68 extends from one edgeof the inclined plate 22.

The end cap 26, shown in more detail in FIGS. 5 a and 5 b, comprises anouter diameter similar to the outer diameter of the sleeve 24 and aninner diameter similar to the inner diameter of the spacers. A hole 70for receiving the shank of the tool bit or accessory is centrallylocated within the end cap 26. An inside face 72 of the end cap isshaped to fit over the inclined plate 22 with a bottom half 74 of theinside face 72 being thicker than a top half 76 of the inside face 72causing the inclined plate 22 to be inclined upon contact with the endcap 26.

After the end cap 26 has engaged the second end of the sleeve 24, theprongs 46 from the inner housing 12 are inserted into a set of prongholes 78 in the end cap 26 and permanently attached via swaging,welding, peening, adhesive bonding, a plastic clip, ultrasonic welding,spin welding, a retaining ring or staking.

FIGS. 6 a and 6 b provide schematic diagrams of an assembled chuck in alocked position while FIGS. 7 a and 7 b provide schematic diagrams ofthe assembled chuck in an open position.

In the locked position, the chuck 10 is generally at rest. As can beseen in FIG. 6, the inclined face 58 and the cross-section 60 in thesecond end 56 of the sleeve 24 rests atop the shoulder 50 of the innerhousing 12 to retain the spherical balls within the holes 52.Furthermore, the first end 54 of the sleeve 24 rests against the tab 68of the inclined plate causing the plate to be inclined against the innerface 72 of the end cap 26. Rotation of the shank in a counter clockwisedirection causes the torsion spring 16 to further tighten its grip onthe shank by decreasing the internal diameter of the spring.

In the locked position, both the compression spring 14 and the torsionspring 16 are uncompressed.

In order to insert a tool bit or accessory into the chuck 10, the chuck10 must be moved from the locked position to the open position. Thechuck 10 is generally held in one hand and the sleeve 24 is retracted bythe user in the direction indicated by arrow 80 of FIG. 7 a causing thecompression spring 14 to become compressed. The movement of the sleeve24 also causes the spring cap 28 central tang 34 to travel along thehelical cam 66, within the hole 44, increasing the internal diameter ofthe torsion spring 16 and enabling the removal and/or insertion of theshank of the tool bit or accessory into the end cap 26 and,subsequently, the first end 36 of the inner housing 12. In general, thehelical cam causes the torsion spring 16 to unwind thereby releasing theshank. The retraction of the sleeve 24 also allows the inclined plate 22to return to a substantially upright position so that the shank may beinserted.

Upon release of the sleeve 24 by the user, the compression spring 14 isreleased causing the chuck 10 to return to the locked position. Thesleeve may also, in the absence of the compression spring, be manuallymoved between the locked and open positions. Along with the compressionspring 14, the central tang 34 also biases the sleeve 24 back to thelocked position by traveling back along the helical cam 66 within thehole 44. Movement of the central tang 34 back along the cam 66 winds upthe torsion spring 16 to decrease the internal diameter of the spring 16thereby causing the torsion spring 16 to grip the shank of the tool bitor accessory. The grip is enhanced by the frictional forces between theinternal dimension of the spring and the outer dimension of the shank.The torsion spring provides torque in a required rotational directionand increased torque application results in an increased gripping forceto reduce torsional or axial slippage.

To further retain the shank from axial movement when the chuck is inuse, the optional inclined plate 22 is used. This stability of theinserted shank is assisted by the spherical balls. During operation ofthe power tool, the rotation of the chuck 10 creates a centrifugal forcecausing the spherical balls to be urged outwardly against the sleeve 24(as shown in FIG. 6). This, in turn, results in the sleeve 24 beingbiased towards the end cap 26 placing a higher force against tab of theinclined plate 22 to further incline the inclined plate 22 against theinner face 72 of the end cap 26. This, in turn, causes the inclinedplate 22 to further bear on the shank of the tool bit or accessory.

Turning to FIGS. 8 to 29, schematic diagrams of second embodiment of achuck for a rotary tool are provided. FIGS. 8 and 9 show the chuck in alocked position while FIGS. 10 to 12 show the chuck in an open position.

A chuck 100 comprises an inner housing 102 (shown in more details inFIGS. 14 to 19), a sleeve 104 (shown in more details in FIGS. 20 to 23)and a spring 106, preferably a torsion spring, (shown in more details inFIGS. 24 to 25).

The torsion spring 106 comprises set of coils 108 with a pair of endtangs 110 and 112 located at opposite ends of the set of coils 108. Thepair of end tangs 110 and 112 point in opposite directions asillustrated in both FIGS. 24 and 25.

Turning to FIGS. 14 to 19, the inner housing 102 is shown in moredetail. The inner housing 102 comprises a first end 114 for receiving ashank from a tool bit or accessory and a second end 116, having a set ofthreads 118, for attaching the chuck 100 to an external drive shaft of arotary or power tool (not shown).

The first end 114, seen as a cylindrical tube 119, comprises a first,angular, slot 120 for receiving one of the end tangs of the torsionspring 106 and for guiding the movement of the torsion spring 106. Asecond, alignment, slot 122, slightly offset or opposite, from theangular slot 120, receives the other end tang and aligns the torsionspring 106 within the first end 114 of the inner housing 102. When thetorsion spring 106 is placed into the first end 114 of the inner housing102, one of the end tangs 110 is inserted into the alignment slot 122and the spring 106 is slid into a central channel provided by thecylindrical tube 119. The other end tang 112 is then received by theangular slot 120 after the spring 106 has been complete inserted intothe central channel.

The inner housing 102 also comprises an annular groove 121 for housing aretaining ring 123 (as shown in FIG. 8) which prevents removal of thesleeve after assembly.

Turning to FIGS. 20 to 23, the sleeve 104 is preferably cylindrical andcomprises a first end 124 having an opening 125 for receiving the shankof a tool bit or accessory and a second end 126 for receiving the innerhousing 102. Between the first end 124 and the second end 126 are aninner housing portion 130, a spring portion 132 and a shank portion 134.As shown in FIGS. 20 to 23, the inner housing portion 130 is larger indiameter than the spring portion 132, which is larger in diameter thanthe shank portion 134. This may be more clearly seen in FIGS. 21 and 23.Between the spring portion 132 and the shank portion 134 is a shoulder136 which contacts the end tang 112 in the angular slot 120 (as shown inFIG. 8).

The inner housing portion 130 generally surrounds the inner housing 102,the spring portion 132 surrounds the torsion spring 106 and the shankportion 134 receives the shank of the tool bit or accessory via theopening 125 in the first end 124.

In operation, the chuck 100 is generally in the locked position, asshown in FIGS. 8 and 9 or the open position, as shown in FIGS. 10 to 12.

In the locked position, the torsion spring 106 is uncompressed with theend tang 112 located at an edge of the angular slot 120 and the end tang110 located in the alignment slot 122. It will be understood that theend tang 110 may also be located in the angular slot 120 while the endtang 112 may be located in the alignment slot 122. The uncompressedtorsion spring 106 grips the shank of the tool bit or accessory in orderto prevent the tool bit or accessory from falling out of the housing. Asis known by one skilled in the art, the rotation of the shank of thetool bit or accessory is generally in a clockwise direction with respectto the user. Rotation of the shank in a counter clockwise directioncauses the torsion spring 106 to further tighten its grip on the shankby decreasing the internal diameter of the spring 106.

In order to change or remove the tool bit or accessory, the chuck 100 isplaced in the open position. By retracting the sleeve 104 away from thetool bit or accessory, in the direction indicated by arrow 140, theshoulder 136 contacts the end tang 112 and directs the end tang 112along the angular slot 120 towards the opposite end of the angular slot120. Since the other end of the torsion spring 106 is restricted frommoving by the inner housing (as shown in FIG. 11), the torsion spring106 is unwound as the end tang 112 is directed along the angular slotcausing the internal diameter of the torsion spring 106 to increase. Themovement of the sleeve 104 also causes the first end 114 of the innerhousing 102 to protrude through the hole 125 in the sleeve 104. Theincrease in the internal diameter of the spring 106 causes the grip ofthe spring 106 on the shank to loosen, allowing the shank to be removed.After the shank has been removed, the user may place another shank intothe inner housing 102 via the opening 125 in the sleeve 104 asschematically showed in FIG. 13. Release of the sleeve by the usercauses the chuck to return to the locked position and the internaldiameter of the torsion spring to decrease which allows the spring togrip the shank of the selected tool bit or accessory.

FIGS. 27 and 28 provide schematic views of the sleeve 104 and the innerhousing 102 of the chuck 100 in the locked and open positions,respectively. FIG. 29 is a schematic diagram of the inner housing withthe end tangs 110 and 112 of the torsion spring 106 inserted into thealignment 122 and angular slots 120. An arrow 182 displays the directionof travel by the end tang 112 when the chuck 100 is being moved from thelocked position to the open position.

FIGS. 30 to 48 show an alternative embodiment of the chuck using aninclined plate to capture the shank of a tool bit or accessory. This issimilar in principle to the mechanism described in application Ser. No.09/783,082, filed Feb. 15, 2001 and assigned to the present inventors'company, Maxtech Manufacturing Inc. In this embodiment, the chuck 200has a sleeve 224 over an inner housing 201, biased against an end cap204 by a spring 202, such as a compression, or biasing, spring. Theinner housing 201 has a central channel for receiving and holding theshank of a tool bit or accessory. The end cap 204 is inserted into acentral opening in the distal end of the inner housing 201. The end cap204, shown in FIGS. 47 and 48, has a central aperture 234 having acomparable size and to that of the shank 212 of a tool bit or accessory211. The end cap 204 has an inner surface, which is on an inclinerelative to the axis of the tool.

Within the sleeve 224, an inclined plate 220 is biased against theangled inner surface of the end cap 204 by a spring 230, when the sleeve224 is in a released position as in FIG. 31. The inclined plate 220 hasa central aperture 222 shaped to receive the shank and having a smalleraxial opening when angled relative to the axis of the tool. This smalleraxial opening grips the shank of the tool bit or accessory when theinclined plate is in the angled position.

When the sleeve 224 is retracted away from the end cap 204, as in FIG.30, the sleeve pulls the plate towards the inner housing 201,compressing the compression spring 202, and straightening the plate 220to an angle at or closer to a 90-degrees to the axis of the tool,allowing for the removal or insertion of the shank of a tool bit oraccessory. The spring 230, shown in detail in FIGS. 36-38, is alsocompressed when the inclined plate is straightened. FIG. 31 shows thechuck 200 when the sleeve is in the locked position and the shank of thetool bit being gripped by the inclined plate 220. In this position, thespring returns to its original shape and butts against the inclinedplate 220.

The spring preferably has an upright loop 231 and an inclined loop 232and a spring tang 233. The spring tang 233 juts out from the externalsurface of the upright loop 231. At one end of the upright loop 231, theinclined loop 232 and the spring tang 233 are connected to the uprightloop 231 on opposite sides of the upright loop 231. The inclined loop232 of the spring 230 is pushed towards the upright loop 231 when theinclined plate 220 is straightened as the sleeve is retracted. Thespring tang 233 is inserted into a corresponding hole 206 in the innerhousing 201, thereby preventing the spring 230 from moving away from theinner housing 201 when the sleeve 224 is retracted or released.

FIGS. 39 and 40 show views of the inner housing. The inner housing 201has a threaded central channel 203 for joining to the rotary tool, and amachined channel into which the shank 212 of a tool bit or accessory 211fits. The outer surface of the inner housing 201 has an annular shoulder205 where the compression spring 202 and the sleeve 224 fits over theinner housing. The inner housing 201 also has an end portion 210 with acentral channel 226 into which the end cap 204 fits. The end portion 210has two slots 207, 208 in the housing, radially opposite one another.The first slot 207 is axially longer than the second slot 208. Theprotuberances 223 of the inclined plate 220 shown in FIGS. 45 and 46,fit into these slots 207, 208. The protuberance in the first elongatedslot 207 moves along the slot 207 when the sleeve 224 is retracted andreleased.

FIGS. 41 and 42 show views of the sleeve. The sleeve 224 is an annularring, preferably made of metal, and is preferably knurled to help theuser grip the sleeve when retracting it. The sleeve has an shoulder 225to limit the movement of the sleeve 224 on the shoulder 205 of the innerhousing.

As seen in FIGS. 43 and 44, the tool shank 212 preferably has a machinedor otherwise flattened portion 218 to allow for torque transfer betweenthe inclined plate 220 and the tool bit or accessory 211. The centralchannel 206 of the inner housing 201 as shown in FIG. 40, the centralaperture 234 of the end cap 204 as shown in FIG. 48, and the centralaperture 222 of the inclined plane 220, as shown in FIG. 46, allpreferably have a similar shape as the machined shank 218.

If desired, then as shown in FIGS. 30 to 33, the end of the tool shank212 may be provided with a flattened tongue 213 which fits in acorrespondingly-shaped slot 209 in the inner housing 201, to providegreater torque to the tool bit or accessory 211 than might otherwise bypossible through just the angled plate. FIGS. 34 and 35 show the toolshank 214 without the flattened tongue and the inner housing without thecorresponding slot.

FIGS. 45 and 46 show views of the inclined plate. The inclined plate 220is preferably a ring of metal with a central aperture 222 shaped toaccommodate a shank 212 from a tool bit or accessory 211. The inclinedplate 220 preferably has at least two protuberances 221 jutting out inradially opposite locations from the circumference of the plate. Theseprotuberances rest in the first elongated slot 207 and the second slot208 on the end portion 210 of the inner housing 201.

Turning to FIG. 49, yet another embodiment of a chuck for use with arotary tool is shown. This embodiment is similar to the one describedabove with respect to FIGS. 1 to 7 with the difference being that thechuck does not include an inclined plate. Furthermore, the inside faceof the end cap 26 may be smooth. This embodiment operates in a manneridentical to the embodiment described in FIGS. 1 to 7.

FIG. 50 is a sectional view of a further embodiment of a chuck for usewith a rotary or power tool.

In another embodiment, the shank of the tool bits or accessories mayinclude notches on the shank to provide additional means of retention(as with standard power bits for screwdrivers) whereby the inner housingcomprises notch receiving means located within said central channel forreceiving the notches on the shank.

Furthermore, the chuck 100 may include a collapsible collet inside thetorsion spring 16. The collet is placed inside the spring anddistributes the holding forces along the length of the shank of the toolbit or accessory.

In yet another embodiment, the chuck 100 further comprises means forattachment with a router or drywall cutting tool such as a Roto-Zipattachment.

An advantage of using a multi-sectional torsion spring instead of asingle piece is that possible to substitute it with other biasing meansthat provide the same torque requirements such as a standard torsionspring, or perhaps springs having irregularly-spaced coils that optimizetorque application.

Another embodiment may be to use separate springs for clockwise andcounter-clockwise torque applications. Currently, most rotary toolsoperate in a clockwise rotation. However, it may be necessary in thefuture to require rotation in the counter-clockwise direction.

Centrifugal mechanisms, such as a scissor mechanism, a dog lock orfly-weights may also be used to tighten the grip of the torsion springaround the shank of the tool bit or accessory during use.

It will be understood that depending on the type of centrifugal movablemeans, the inclined face 58 may be a wall which is perpendicular to thecross-section 60.

The chuck may further comprise an expansion spring near the end cap thatexpands when the central tang is rotated by the helical cam, to preventthe sleeve from returning to its normal position before the shank isinstalled.

In order to determine if the shank of the tool bit or accessory has beeninserted to the correct depth, the chuck may further comprise means forrecognition/detection of the insertion depth of the shank such as via atransition element.

To ensure a consistent internal diameter of the torsion springs, sincethere is typically a fair degree of variance in the manufacturingprocess, the internal diameter of the torsion springs may be altered byvarious methods such as grinding, machining or honing. In some cases,very little metal may be removed, and in other cases more. An addedadvantage of this operation is that it in effect flattens the innersurface of the springs, providing more surface area for contacting theshank.

Conventional springs have a round cross-section, resulting in “lines” ofcontact between the spring and the piece to be gripped. Springs havingdifferent cross-sections may also be utilized, such as square,rectangular, etc. When these are used, the area of contact is larger andthe effective gripping force increases.

In yet another embodiment, if the key is not integrally formed as partof the sleeve, both the cylindrical tube and the sleeve have alignmentslots for receiving a key. The size of the key is manufactured such thatits length is longer than the length of each slot so that the key doesnot slide out of either of the two slots.

In addition to the variations described above, for example, the sleevecould be configured so as to actuate the torsion spring by rotation ofthe sleeve relative to the housing, though the preferred embodimentinvolves axial movement of the sleeve as described above.

In yet another embodiment, the chuck comprises an expandable andcollapsible device actuated by the sleeve that may be either manuallybiased or spring biased. When the sleeve is pulled in one direction, thedevice expands permitting tool bit removal and replacement of anothertool bit. When the sleeve is urged in the opposite direction, the devicegrips the shank of the tool bit and locks the shank in positioneliminate the need for a torsion spring. The end of the tool shank maybe provided with flats or a non-circular shape that fits into acorrespondingly shaped recess on the housing to provide additionaldrive. The expansion and gripping actions of the device may also beachieved by rotational movement of the sleeve.

Conventionally, chucks are designed to accommodate to shanks of toolbits or accessories of varying size, whereas one aspect of the presentinvention is related to chucks and tool bit shank combination of a fixedsize conforming to known tolerance rangers for manufacture.

The above-described embodiments of the present invention are intended tobe examples only. Alterations, modifications and variations may beeffected to the particular embodiments by those of skill in the artwithout departing from the scope of the invention, which is definedsolely by the claims appended hereto.

1. A chuck for retaining the shank of a tool bit or accessory insertedin a central channel at a distal end of said chuck, comprising at leastone torsion spring mounted axially within a housing and having an innerdimension and shape comparable to the shank's outer dimension and shape,and mechanical means for winding and unwinding said torsion spring torespectively grip or release said shank, wherein said at least onetorsion spring has a resting inner dimension less than said shank'souter dimension, such that said torsion spring must be partially unwoundfor said shank to be inserted.
 2. A chuck as in claim 1, wherein saidmeans for winding and unwinding said torsion spring comprises a movablesleeve, axial movement of said sleeve producing rotation of said atleast one torsion spring.
 3. A chuck as in claim 2, wherein said sleevehas an internal profile configured to act on a moveable tang portion ofa said torsion spring to produce movement of said tang portion when saidsleeve moves axially, said movement of said moveable tang portionwinding or unwinding said torsion spring.
 4. A chuck as in claim 3,wherein a said torsion spring has a secured end tang and a free endtang, said free tang constituting said moveable tang portion, wherein aportion of said sleeve contacts said free end tang to produce saidmovement, and wherein said free end tang rides in a slot in saidhousing, said slot being angled away from an axial direction such thatmovement of said sleeve causes said tang to move along said slot,thereby winding or unwinding said torsion spring.
 5. A chuck as in claim3, wherein a said torsion spring has opposite end tangs which aresecured, and a central tang, said central tang constituting saidmoveable tang portion, wherein said torsion spring is wound in oppositedirections on opposite sides of said central tang portion, such thatmovement of said central tang portion produces winding or unwinding ofsaid torsion spring.
 6. A chuck as in claim 5, wherein said sleeve hasan internal profile angled away from an axial direction, such thatmovement of said sleeve causes movement of said central tang portion bysaid internal profile acting against said central tang portion.
 7. Achuck as in claim 6, wherein said central tang portion has an overlyingcap thereon, said cap extending through a circumferential slot in saidhousing for engagement by said internal profile of said sleeve.
 8. Achuck as in claim 2, further comprising a biasing spring arranged tobias said sleeve to an extended position wherein said torsion spring hasan inner diameter less than the shank's diameter, to grip said shank,and wherein moving said sleeve to a retracted position unwinds saidtorsion spring to release said shank.
 9. A chuck as in claim 8, furthercomprising centrifugally-movable means between said housing and saidsleeve, arranged such that centrifugal outward movement of saidcentrifugally-movable means prevents retraction of said sleeve andthereby prevents releasing of said shank.
 10. A chuck as in claim 9,wherein said centrifugally-movable means comprises a plurality of balls,and wherein said sleeve has a surface engaged by each ball when saidballs move outwardly, said engagement preventing retraction of saidsleeve.
 11. A chuck as in claim 1, wherein said shank is cylindrical.12. A chuck as in claim 1, further comprising at least one cross memberdisposed within said housing and having a fixed axial aperture, saidaperture sized to receive said shank with minimal clearance, therebyurging said tool bit or accessory to remain axially oriented.
 13. Achuck as in claim 1, wherein there are at least two said torsionsprings.
 14. A chuck as in claim 13, wherein at least one said torsionspring is oriented in one rotational direction, and at least one othersaid torsion spring is oriented in the opposite rotational direction,whereby said shank is secured in either direction of rotation of saidchuck.
 15. A chuck as in claim 1, further comprising a plate positionedin said chuck and having a central axial aperture which is slightlylarger than a cross-section of said shank when said plate is at 90degrees to the axis, but which corresponds in cross-section to saidshank when said plate is angled away from 90 degrees, said plate beingpivotable such that extraction of said shank increases said angling awayand thereby tightens said plate on said shank to prevent extraction,further comprising means for straightening said plate towards the 90degree position, to permit extraction of said shank.
 16. A chuck as inclaim 2, wherein said sleeve is die-cast metal.
 17. A chuck as in claim1, wherein the internal diameter of the torsion springs has been alteredby mechanical means selected from the group consisting of grinding,machining, honing and other metal-removing means.
 18. A chuck as inclaim 1, further comprising a collapsible collet inside said torsionspring, for distributing shank-retention forces along a length of theshank.
 19. A chuck as in claim 2, further comprising an end cap on anend of said sleeve, permanently attached thereto by a process selectedfrom the group consisting of swaging, welding, peening, adhesivebonding, clipping via a plastic clip, ultrasonic welding, spin welding,staking, or retaining via a retaining ring.